Modified Suzuki angiographic stages
| Stages | Angiographic Findings |
|---|---|
| I | Mild-to-moderate stenosis around carotid bifurcation with absent or slightly developed ICA Moyamoya:* almost all of both ACA and MCA branches are opacified in antegrade fashion |
| II | Severe stenosis around carotid bifurcation or occlusion of either of proximal ACA or MCA with well-developed ICA Moyamoya:* either ACA or MCA branches or both are clearly defective, but at least several of ACA or MCA branches remain opacified in antegrade fashion |
| III | Occlusion of both proximal ACA and MCA with well-developed ICA Moyamoya:* only a few of either ACA or MCA branches or both are faintly opacified in antegrade fashion through the meshwork of ICA Moyamoya |
| IV | Complete occlusion of both proximal ACA and MCA with absent or small amount of ICA Moyamoya:* without opacification of either ACA or MCA branches in antegrade fashion |
Note:—Data were modified from the staging system proposed by Suzuki and Takaku.1 When the proximal ACA was hypoplastic, stage was determined by evaluating the proximal MCA involvement, opacification of MCA branches, and degree of development of ICA Moyamoya. ICA indicates internal carotid artery; ACA, anterior cerebral artery; MCA, middle cerebral artery.
* ICA Moyamoya indicates Moyamoya vessels at or around the terminal part of the ICA.